Lock-out telephone system.



A. F. POOLE.

LOCKOUT TELEPHONE SYSTEM. APPLICATION FILED DEC. 30, 1905. RENEWED SEPT.27, 1907.

PATENTED FEB. 4, 1908.

actuate the electromagnetic controlling UNITED STATES PATENT OFFICE.

ARTHUR F. POOLE, or wear.

LING, wns'r VIRGINIA.

LOCK-OUT TELEPHONE SYSTEM.

Specification of Let ters Patent.

Patented Feb.4,1908.

7.1 07. Serial No. 394.810.

To all whom it may concern: line. 7 Notwithstanding 'these results,which Wheeling, in the county of Ohioanjd State of th ings,io rming apart of this specification.

My invention relates to artyline teler phone systems, and particu arlyto an im- 'ockou't mechanism. roved lock-out system for useinconjuncinvention is of pecul maybe used with anyof the commercialstems, in some of which tion therewith. it

My invention is applicable to central enselective signaling sy ergyparty lines, and any number of subany additional impedance connectedinto a stations may be connected with each line. substation circuitwould interfere with the The system may be used in connection withoperation of the selective signaling appa any of the selective signalingsystems of the l ratus. As will more fully appear, the cir- Y mplo'yedin carrying In accordance with my invention, the out my invention areextremely si n lo, and" telephonic apparatus at each substation, many ofthe pie that is, the transmitter and receiver, and ne currents, isnormally inoperative. 4

of this controlling mechanism is required in -for talking an order toplace the'teleplionic apparatus in pliedfrom a'common source operativecondition. The operation of the central office. I have shown thetelephone i l lines X and turn is controlled by the amount of energy thecord circuit The line limbs ajan electromagnetic controlling mechanismin available in the line. When a single subscriber on agiven lineinitiates or answers in call by removing his receiver from the hook,

the available energy will be 'sufiicient' to mechanism to renderoperative the tele-, phonic apparatus at his substation, but b. uponsuch use of. the line'by the first substation the available energy inthe line is so P reduced that the electromagnetic controlling quently itis impossible for the second suband line circuits in any 0 scriber torender operative his telephonic known to the art.

apparatus. This lock-out condition will be Each of the telep maintainedas long as the telephonic appaany desired number. of, substations, ratusat the first substation is in use. -In 1 the sake of illustration I haveshown the line connected withtwo. part and B, while the line Y is co Ateach of the suitable accordance with my invention, however, I l Xprovide means wherebya second substation A line are connec commonbattery 2, is connected throng the springj ack contact Thecord circuitis equippe 4 for conne in bridge of the c1r- 6, 7 and 8 serve to tgenerator 9 with A supervisory rennected with the cord the ways welerators listening key on a given line may be signaled in answer tosubstation I).

l by another subscriber on that same l stations is provided esence ofany part art." cuits and apparatus e a springjack 1. The line ted alsowith one the other po e h the indicators 3, Sand s with the'line limbs11,

erators telephone set 5 p cuit and theringing keys mechanism at anothersubstation Will' not connect the ringing curren be operated upon theremoval of the assothecalling c ord strands. ciated receiver fromits'hook, and conse lay 10 is suitably co Be it known that I, ARTHUR F.Poona, a may be accomplished 'by the use of citizen of the United,States, residing at vention, the app ere will be no impedance WestVirginia, have invented a certain new resulting from the introduct anduseful Improvement in Lock-Out Telemagnetic controlling mechanism honeSystems, of which the following is a circuits. Furthermore thedisposition of the full, clear, concise, and exact description,reielectromagnets employed in carrying out my erence-being had to theaccompanying drawinvention is such that there is impedance in a subaratus s to voice currents ion of the electronormallyno t due to the ofthe telephonic or For this reason my iar advantage in that stationcircui cos of apparatus w cessary for telephonic transmission are anyother apparatus which may be required also utilized as parts of thesignaling system for the transmission or' translation of voice peglse.

Y In accordance with my invention, electroreference to magneticcontrolling mechanism is provided a which shows two telephone 1 at eachsubstation, and a suitable actnatioii together at invention will bebetterunderstood by ether throu l b of eac limbs a of each hone linesmay e substations nnected with partyline subtelephonic apthe art, is onaccount of the fact that the ring sistance winding h is connected.

mechanically connected with the. switchhook nected with the line limb towhich the high resistance winding of the relay is connected,

paratus comprising a rec i er 12, a transmitl ter 13. and a condenser IF. The switch'hook 11 is equipped with ccntact springs, which serve toalter the electrical connections due to the movement 01 the switch hook.It is to be noted that the telephonic apparatus at the substation doesnot include an induction coil nor an impedance coil which is specially,provided for the telephonic circuit alone.

At each substation there is a relay R, and in the preferred embodimentof my invention the relay has two windings. a high resistance winding71, and a low resistance winding Z. The armature 16 of the relay ispermanently connected with one terminal of the receiver 12. The normallyclosedback contact 17 of the relay is connected with the other termi nalof the receiver, thereby short-circuiting the receiver and rendering itinoperative at all times when the armature of the relay is in its normalposition against the back contact 17. One terminal of the high.resistance winding h is connected with the contact spring 18 associatedwith the switch hook. The other terminal of the high resis'ance windingis connect-ed with one or the other of the line limbs. At thesubstationA it is connected with the limb 7), while at substation B itis connected with the line limb c. This, as will be readily understoodby those skilled in ing currents tor actuating the signal bell at thesubstation A traverses the line limb Z) to ground, while at substation Bthey traverse the line limb u, to ground. At each substation is provideda signal bell 14 and a condenser 15, both being connected as shown inthe drawing. One terminal of the low resistance winding 1 of the relayis connected with the frontcontact 19 associated with the armature 16,and the other terminal of this winding is connected through the manuallyoperated switch or key 20 with the same line limb as that to which oneterminal of the high re- The telephone transmitter 13 is preferablyconnected with the armature 16 and with the spring contact 18, whilethat terminal of the receiver which is connected with the contact 17 isalso connected with a contact 21 associated with the contact spring 22,but normally disengaged therefrom. The contact spring 22 is butinsulated therefrom and electrically conthis connection, however, beingan inductive connection only on account 01' the interposition of thecondenser 15. The switch hook at substation A is connected with the linelimb a.- At substation B the switch hook is. connected with the linelimb b.

The selective ringing keys 6 and 7 at the central station are arrangedin a well known manner so that the generator 9 may send-signalingcurrent through the signal bell at one of the substations when the key 6is actuated,

. and through the signal bell at-the other substation when the key 7 isoperated. In the drawing I have shown the answering side of the cordcircuit connectedwith the line X by way of the associated springjack andthe calling side of the cord circuit as connected with the line Y, thesubstation illustrated as connected i with the line Y being arranged sothat the signal bell will be actuated by an alternating current overboth limbs of the metallic line. As will be readily understood by thoseskilled in the art, the ringing key 8 at the central station isconnected with the enerator 9 in such a way that an actuation 0 this keywill send a current over the two limbs of the metallic line in a mannersuitable for actuation of a'si nal bell connected as shown at substation]3 on the line Y. Any number of substations arranged like that shown atD may be connected with a metallic line, and the. ap lication ofcurrents of suitable polarity or iiequency may be relied upon to selectand ring the desired substation.-

A description of the operation of the system here shown will illustrateits novelty andusefulness. The receiver at substation B is shown removedfrom the switch hook and it may be assumed that the subscriber at thissubstation hasinitiated a call to be answered at the central station.The cordconnecting apparatus is normally disassociated with thetelephone lines and current will therefore flow from the common battery2 through the indicator 3, the springjackcontact-s, the line limb b, theswitch hook at the substation B, the associated contact spring 18immediate energization of thisrelay to at-v tract its armature 16, thusopening at once the short-circui-t about the receiver 12. Fur-'thermore, the attraction of the armature 16 causes an engagement of thearmature with the front contact 19, thereby affording a new path atsubstation B throughwhich current may [low from one line limb to theother. This additional circuit may be traced as follows: from the linelimb I) through the switch book 11 at substation B, through the springcontact 15f, the transmitter 13, the armature 16, the front contact '19of the relay R, the low resistance winding 6 ct this relay and the key20 to line limb a. It will be apparent that the closure ot'a circuit'atsubstation through the high resistance winding h of the relayimmediately reduces the voltage The available for the actuation ofapparatus at any other station on the same line, but the closure of anadditional low resistance circuit through the other Winding of the relayimmediately upon the attraction of the relay armature 1.6 causes, a verymuch increased current to flow through the circuits at substation B,tgigby reducing still further the line volta e ilable foractuationofapparatus at ot' er substations on the same line. In this wayall of the other substations on this line are scriber can put histelephonicapparatus' into operative condition for listening upon theline. The attraction of the armature 16 at the substation B ismaintained'not only by the flow, of currentthrough the high resist-'rent through thehigh resistance winding 72 of a relay at any othersubstation on the line surficient to cause the associated armature 16tostart or to move far enough tov engage its front contact 19, .itreguiring more energy to start the armature t an to hold it in itsactuated position. Therefore the receiver at another station will remainshort-circuited and transmitter circuit will be open by virtue of theinaction ofthe armature of the assoeven though the receiverat thisciated relay; substation be removed from its switch hook to closecircuit the associated high resistance winding h.

Referring now, to the apparatus at substation B, it will be seen thatwith the switch hook in itsupper position there are three parallelcircuits through the substation a paratus. traced through the ,twowindings of-the'relay -R there is a circuit through the telephonereceiver through which telephonic voice currents may flow; This circuitmay be traced from the'line limb or through the condenser 15, the springcontact 22, contact 21, the receiver 12, the transmitter 13, the springcontact 18, the. switch hook '11, and thence to the line limb b. denserincluded-in this circuit it will not, of course, convey the directcurrent necessary for the operation of thetransmitter" 13. The directcurrent for the operation of the transmitter is conveyed through thecircuit previously traced and includes the-low resistance winding Z ofthe relay RL: This electrornagnet winding Z serves, therefore, not onlyto provide a low resistance ath between-the line limbsto deprive 0t orsubstations of a current suflicient for the actuation of their relaysand to assist in-lnaintaining the energization of its own electromagnetlocked out so that no other sub-- ance is so In addition to .thecircuits alrea y 'ciated with the line X, am

On account of the concore for the retentionof the associated armae ture,but also to provide the impedance C011 necessary in a telephonicsubstation set where a condenser is included in circuit with thereceiver. The impedance coil formed by the low resistance winding 1serves to kick the voice currents through the receiver and seriallyconnected condenser. Onaccount of the.ir npedance of the relaywindings'incoming voice currents will be forced to follow almostexclusively the path through-the condenserand serially connectedreceiver. Al-

though the high resistance winding of the relay is connected in a branchof the low resistance winding and transmitter, its resisthigh thatpractically all of the di rect current will flow through the transmitterand low resistance winding. The impedance ofthe high resistance Windingh is so great also that it does not serve to short-circuit the voicecurrents set up at the same substation. The condenser '15 revents theflow of direct current through t e assaciated receiver, thus preventingthe demagnetiza tion of the receiver. A-s ingl e condenser at eachsubstation when connected in accordance with my invention serves twopurposes.

Normally it preveiits the flow of battery current from the line throughthe associated signal bell to ground and serves-to cqnvey thealternating or ulsatin'g ringing current. When the switch is connectedin series with the receiver to transmitvoice currents and to prevent thepassage of direct current. able .to make the. signal bells of'-comparatively high impedance to prevent the leakage of voice currents; Theconnection of the signal bells to opposite limbs of the line serves tomaintain the inductive balance thereof.

The 0 erator atthe central ol'lice responrh ins to her answering plug ina s from'the calling subscriber that a connection ook is raised thecondenser.

I find it prefere signal of the indicator 3, inserts r1ng ack assouponlearnlng is desired with substation D, she inserts her calling plug intothe jack associated with the a line Y and signals the subscriber atsubstation D by actuating the ringing key 8 The subscriber at substationD in answering the.

call removes hisreceiver from theswitch hook 11, thereb causing the fiowof current through the hig resistancewinding h of his relay R, and itbeing assumed that none of the other substation sets connected with thisline are already in use,the"pressure in the line Y will be sufficient toenergize the relay Ittocause the attraction of the armature, thusremoving the short-circuit from the receiver and closing circuit throughthe low resistance winding 1 of the relay-and thus completlng thetelephonic circuit at the substation I). The removal of the receiverfrom the switch hook at substation D serves to lock out all of the othersubscribers connected on line Y.

It'is sometimes desirable that substations connected with the same linemay be connected with each-other for conversation, and

this, under the conditions thusfar described,

. wouldbeimpossible, owing to the look-out feature of'my invention. Ateach substation, however there -is provided the key20,

. reduced as when the low resistance path is -closed between the linelimbsat the substation I) and the line pressure-will then bev sufficientto cause a current to flow through the high resistance winding of therelay at substation A, this current being suilieient to move thearmature 16 at substation A to open .the short-circuit about thereceiver upon the removal of the receiver from the switch hook atsubstation A in response to the signaling current which the operatorsends over the line to actuate the signal bell at the substation A. Theopening of the low resistance circuit at substation B by depressing thekey 20 will not afi'ect the receiver circuit at substation B and thecalling subscriber therefore can hearwhen the subscriber at thesubstation A answers. When he hears the answer he immediately releaseshis key 20, whereupon the low resistance circuit at substation Bprovides current for transmission purposes and the conversation betweenthe connected subscribers may proceed i'nthe usual 'way. Although thelow resistance circuits at the substations A and B are both closed, theavailable energy will be sullicient to hold the armaturcs thereat butwill not be sullicient to start the armature at any other-substationwhen the receivcrat the other substation is lifted during conversationbetween A and B.

'.l.t will be apparent to those skilled in the art that the lock-outsystem herein described is simple. and 'clliciei'it, and that therequired .results are accomplislmdwithout the provision of expensive andcomplicated apparatus in addition to that usually required in a commonbattery substation set. The high resistance relay winding, beforestated,

and the low resistance winding also both prevent' short-circuiting ofvoice currents and deflect them through the rccei ver and seriallyconnected condenser. At the same time If we assume that the subbothwindings cooperateto maintain the energization of the relay and theattraction of its armature to maintain the necessary connections duringconversation, and, furthermore, the electromagnet which acts "tooperate-the armature 16 serves also for the impedance coil of thetelephonic circuit, no

other impedance coil or induction coil being required; The condenseralso performs the' various functions heretofore ascribed to it. While Ihave herein shown and described a preferred embodiment of my invention,I do not wish to be limited to this precise arrangement, as changes'mayreadily be made by those skilled in the art without de arting from thespirit of my invention. urthermore, I do not wish to limit myself to anyparticular selective signaling system'nor to the precise central stationarrangement herein shown, since my improved lock-out system maybeemployed in connection with any selective signaling system in thecentral station equipment necessarily associated therewith.

hat I claim as new and desire to secure by- Letters Patent is 1.. In atelephone system, the combination with a party line, of a plurality ofsubstations connected. therewith, telephonic apparatus at eachsubstation, a source for supplying current to the line and substationsarelay at each substation for controlling the operativeness of thetelephonic apparatus thereat, said relay having two windings, means uponactuz-ition o'l. substation apparatus for eausing first current flowthrough one of said windings to energize therelay and then current ilowalso through the other winding to assist. in maintaining energization ofsaid relay, energization of said relay causing the telephonic apparatusto become eflective.

2. In a telephone system, the combination with. a line, of a pluralityof substations connected therewith, a source for supplying current tothe line and substations, telepho'i'iic and switching apparatus at eachsubstation, a relay for controlling the operativcness of the telephonicapparatus, said relay having two windings, actuation of switchingapparatus at the substation causmg first the closure of a circultincluding one of said. windings, -means adapted upon current llowthrough said winding to causev the closure of a circuit in parallel withsaid first circuit and inclmling telephonic apparatus and the otherrelay winding, said circuits being in parallel and affording a paththrough the substation for current from said source, said first windingbeing of high resistance wlwreby the greater part of said current willflow through the elrciut containing the telephonic apparatus and theother winding, said telephonic apparatus being rendered effective uponmy tuai ion of said relay.

)3. In a telephone system, the combina io with a line, of a substationconnected with, a source for supplying current to the line andsubstation, telephonic and switching apparatus at the Substation, arelay at the substation contro the telephonic apparatus,: two windingsfor said relay, actuation of switching apparatus at the substationcausing first closure of a circuit including one of said windings where-.by the relay is energized to render the telephonic apparatus operative,a second circuit closed upon actuation of the relay and 1ncludingtelephonic apparatus, said windings acting cumulatively to maintainenergization of the relay, said first winding being of high resistancewhereby the current ow through the substation is all 'coniined,practically to the circuit containing the telephonic apparatus.

4. In a telephone system, the combination with a line, of a substationconnected there' with, a source for sup lying current to the line andsubstation, telephonic apparatus at the substation normally ineffective,at the substation having two windings, actuation of switching apparatusat'the substa- 7 line and'substation, te

" station causing current [winding to assist tion causing current flowthrough one of said windings to energize the relay to render thetelephonic apparatus operative, winding of the relay being includedincircuit upon energization of the relay by the first said first windingin maintaining actuation of the relay. s 5, 111a telephone system, thecombination with a line, of a substation connected there with, a sourcefor sup lying current to the ephonic apparatus at the substationnormally at the substation havingtwo windings, actuation of switchingapparatus at the subflow through one of said windings to energize therelay to render the telephonic'apparatus operative, the second winding'ofthe relay being included in circuit upon 'energization of the relayby the first winding to assist said first winding in maintainingactuation of the relay, said windings upon action of the relay beingincluded inparallel circuits.

6. In a telephone system, the combination with a telephone line, of asubstation connected therewith, a source for supplying current to theline and substation, main switching apparatus at, theisubstation,auxiliary switching apparatus at the substation normally disposed torender the telephonic apparatus inoperative, a relay controlling saidauxiliary switching rnechanlsm, two windings for said relay, actuationof the main switching mechanism causing closure of acireuit through thesubstation containing one of said windin s whereby said relay becomesactuated am said auxiliaryswitching mechanism movedto allow thetelephonic apparatus to become operative,

a relaythe second.

ineffective, a relay closure of a circuit through the second .wmd'

ing of the relay w hereafter both windings are l effective inmaintaining actuation of the relling the operativeness of I lay.

*ings, actuation of themain sw'itc thereby connected with the actuationof supplying the linean 7. In a telephone system, the combination with aline, of a substation connected there: with, a source for supplyingcurrent to the system, main switching mechanism atthe substation,telephonic apparatus at the substation normally disconnected from theline independently of the main switching mechanism, a relay-controllingthe connection of said telephonic apparatus with the line, two

windings for said relay, means upon actuation of themain-switching.mechanism for allowing current flow through one of saidwindings to cause actuation of the relay, means u on actuation of therelay by said first win ing for causing closure of a circuit through thesecond winding and connection of the telephonic apparatus; with theline, said two windings then acting cumulatively to maintain actuationof the relay.

8. In a'telephone system, the combination with a line, of a substatioiiconnected therewith, a source of current for connection with thesubstation, main switching mechanism and telephonic apparatus at thesubstation, said telephonic apparatus being normally disconnected fromthe line independently of the mam switching mechanism, a rela forcontrolling the-connection of the telep onic apparatus with the line andhavingqlzwo windng mechthe closure of a circuit through one winding ofthe relay whereby said relay is actuated, actuation of the relay causingclosure of a second circuit throu h the substation, said second circuitinc udin the other winding of the relay and. telepdionic anismcausingapparatus, said telephonic'apparatus being l nc and sai windings bothactive in' maintaining actuation of the relay.

9. In a telephone system, the combination with a line, of a substationconnected therewith, a source substation, switching mechanism at thesubstation, telephonic apparatus at the substation normally inefiective,a relay at the substation controlling the telephonic apparatus, meansupon actuation of the switching mechanism for causing closure of a pathfor current flow through the substation including one winding of therelay whereby said relay is actuated to render the telephonic apparatuseffective, and a second winding for the relay connected in circuit uponactuation thereof to assist said first winding in maintaining actuationof the relay. l i

10. In a telephone system, the combination with a telephone line, of asubstation connected therewith, a source of current for for supplyingcurrent to the d substation, telephonic connected from the line, twonormally open for controlling one path, a relay for controlhug thesecond path, two windings for said -relay, one of said windingsbeingincluded in said first path and adapted upon actuation of theswitching mechanism to cause actuation of said relay (x hereby saidsecond path is closed, said second path containing said telephonicapparatus, and means upon actuation of said relay by thexlirst indingfor causing said second pinding to be included in circuit to assist saidfirst winding in main taining actuation ofthe relay.

11. In a telephone system, the combination with, a telephone line, of asubstation connected therewith, a source of current for supplying theline and substation, telephonic apparatus at the substation normallydisconnected from the line, two normally open parallel aths at thesubstation for current flow, mainv switching mechanism at the substationfor controlling one path,- a relay for 'controlhn the second )ath, twowindings for said rdlay, one of sai windings being included in saidfirst path and adapted upon actuation of the switching mechanism tocause actuation of said relay whereby said second pathis closed, saidsecond path including the tele honic ap )aratus and the second windingior said re ay, said second winding assisting said first winding inmaintaining actuation of the relay.

12. In a telephone system, the combination with a line, of a substationconnected therewith, a source for supplying current to the line andsubstation, tele honic apparatus at the substation, relay mecfiianismnorm-ally disposed to render the telephonic apparatus ineffective, ahigh resistance and a low resistance winding for said relay, switchingmechanism at the substation adapted upon actuatlon to close first acircult through said high resistance winding tocause actuation of therelay mechanism, whereby the telephonic apparatus is rendered eiiective, and a second.-

clrcuit closed through said low resistance winding upon actuation of therelay for assisting'the high resistance windingin maintaining actuationof the relay.

1.3. In a telephone system, the combination with a telephone line, of asubstation connected therewith, a source of current for supplying theline and substation, telephonic apparatus at the substation normal ydisparallel paths at the substation for current flow,'ma1n switchingmechanism at the sub station for controlling one path, a relay forcontrollin the second path, two windings for said re ay, one of saidwindings being in-. cluded in said first pathand adapted upon actuationof the switching mechanism to cause actuation of said -relay'iwherebysaid second path is closed, said second path in cluding the telephonicapparatus and the second winding for said relay, saidsecondwin'dingassisting said first winding in maintain ing actuation of the relay, thefirst path being of high resistance and the second path containing thetelephone apparatus being of low resistance whereby practically all thecurrent flow will be through said second path and telephonic apparatus.

H. in a telephone system, the combina- I tion with a telephone line, ofa substation connected therewith, a source of current for supplying theline and substation tele honic apparatus at the substation normal ydisconnected from the line, two normally open parallel paths at thesubstation for current llow, main switching mechanism at the substationior controlling one ath, arelay for controlling the second pat 1, twowindings for said relay, one of said windings being in cluded in said.first path and adapted upon actuation of the switching mechanism tocause actuation of'said relay whereby said second path is closed, saidsecond path including the teleihonic ap ara us and the second, windingior said re ay, said second winding assisting said first winding inmaintaining actuation of the relay, said first path being of high im)edance whereby telephonic currents are de ected through the secondpath.

1.5. In a telephone system, the combination with a line, of a substationconnected therewith, a source for supplyingcurrent for the line andsubstation, main switching windings for said relay mechanism, means uponactuation of the switching mechanism for closing a circuit through oneof said windings to cause actuation of the relay whereby theshort-circuit is removed from the telephonic apparatus and otherapparatus connected with the line, actuation of the relay mechanismcausing also inclusion in a circuit the second winding of the relay,both windings then acting cumulatively.

16. in a telephone system, the combination with a telephone line, ofa'substation connected therewith, a source of current for supplying theline and substation, switching mechanism at the substation, relaymechanism normally causing the telephonic apparatus to beshort-circuited and disconnected from the line, a high resistance and alow resistance winding for said relay, actuation of the switchingmechanism causingmirrent flow through the high-resistance windingwhereby the relay mechanism becomes actuated to open the short-circuitand to conactuation of the relay mechanism-causing also closure of acircuit in parallel of the high resistance winding and through the lowresistance winding whereby a low resistance path is afforded through thesubstation and said high resistance winding assisted. in

maintaining actuation of the relay mech-' l nected from the line,switching mechanism anism. 1

17, In a telephone system, the combination with-a line, of a pluralityof substations connected therewith, a source of current forsupplyinghthe line and substations, telephonic apparatus at eachsubstation, relay mechanism at each substation normal-1y causingtelephonic fective, switching mechanism at each substation, actuationof'the switching mechanism at onesubstation causing-closure of,a highresistance path through the relay mech anism whereby said mechanism isactuated "to render the telephonic apparatus operacausin the closureactuation ofthe .relay mechanism of a low resistance path through therelay mechanism in parallel to the high resistance, the current flowfrom said source upon connection of the low re-. sistance path at theone substation being tive,

insu'fl icient to cause actuation of a relay at another through .its--high resistance path upon actuationof the switching mechanism at theother substation whereby theltelephonic apparatus at other substationsare maintained iii-inoperative condition.

18. in a telephone system, the combination with a line, of a pluralityof substations connected therewith, a source of current for supplyingthe line and substations, telephonic apparatus at eachsubstation, relaymechanism at each substation normally causing telephonic apparatusthereat to be inefl'ective, switching mechanism at each substation,actuation of the switching mechanism at one substation causing closureof a high resistance path through the relay mechanism whereby saidmechanism is actuated to render the telephonic apparatus operative,actuation of the relay mechanism causing the closure of a-low resistancepath through the relay mechanism in parallelto the high resistance,connection of the low resistance path at the one substation'preventinsutllcient current through any other substation to eause actuat on .ofthe relay at said other substation throughits high-resistancen'atmupdn'actuation of the switchin mechanism at 'said other substationwherebythe ,telephonic apparatus at other substations .are maintainedin' inoperative condition, and means at each substation for opening thelow resistance, path whereby upon actuation cause actuation of the relaymechanism at any ing mechanism at the other substation.

apparatus thereat to be inef-.

Ofisaid means at the on'e 'sub' station there will be'su'tlicientcurrent flow to 19. Ina tele h one system, the combination with a teephone line, of substations connected'therewith, a'source of current forsupplying the 'line and substations, telephonic apparatus. at eachsubstation, relay mechanism at each substation normally-causing thetelephonic apparatus to be disconat each substation, means uponactuation of the switching mechanismat one substation for causingcurrent flow through a high "resistance path through said relaymechanmechanismis actu.

ism whereby said relay ated, a low. resistance path closed through saidrelay mechanism in parallel with the high resistance path upon actuationof the relay mechanism, said low resistance path including thetelephonic apparatus whereby said apparatus is connected with the line,the energy from said source upon current flow through both paths at theone substatio'n being insufficient to cause actuation of the relaymechanismat another substation through the high resistance path thereofwhereby said other substations are locked from telephonic service. 1

20. In a telephone system, the combination with a telephone line, ofsubstations supplying the line and substations, telephonic apparatus ateach substation, relay mechanism at each substation normally' causingthe telephonic apparatus to be-disconnected. from the line, switchingmechanism. at each substation, means upon actua- 4 connected therewith,a source of current for tion of the switching mechanism at one sub stalon for causing current flow through a high resistance path mechanismwhereby saidrelay mechanism is actuated, a low resistance path closedthrough said relay mechanism in parallel with the high resistance pathupon actuation of the relay mechamsm, said low resistance pathincluding. the telephonic apparatus whereby said apparatus is connectedwith the line, the energy from said source upon current flow throughboth paths at the one substation being insuflicient to cause actuationof the relay mechanism at another substation through the high resistancepath thereof "whereby said other substations are locked from telephonicservice, and addi-v tional switching means at each substation,-actuation of said additional switching means at the onesubstation'causing the low resistance path to be rendered ineffectivewhereby .said source may supply sufficient energy through said relay"through the high resistance path .of the relay mechanism at anothersubstatipn to allow actuation of the relay mechanism at the othersubstation.

21. In'a tele hone system, the ,combina-' tion with a te ephone line,ofsubstations connected therewith, asource for supplying current to theline and substations, transmitting and receiving 'mechanism at eachsubstation, relay mechanism at each substation normally causing thetransmitting; mechanism to be disconnected from the line, switchingmechanism at each substation, ,means upon actuation of the switchingmechanism at one'substation for causing current flow through a highresistance path of" the relay mechanism whereby said relay mechanism isactuated'td cause the transmitting mechanism to be connected with theline, a

low resistance path for the relay mechanism connected in circuit uponactuation of the relay mechanism, said low resistance path causingsuflicicnt diminution of the energy from said source to preventactuation of the relay mechanism atanother substation through the highresistance path thereof whereby other substations are locked fromservicc, and a HOD-llilPGtlzlHCG path closed through the receivingmechanism at the substation about the relay mechanism upon actuation ofthe relay mechanism.

22. In a telephone system, the combina tion with a-telephone line, ofsubstations c'on' nected therewith, a source for supplying current tothe line and substations, telephonic apparatus at each substation, relaymechanism controlling! the connection of telephonic apparatus with theline, switching mechanism at each substation, actuation of the switchingmechanism at one substation causing closure of one path through therelay 111echanis1n"'wl'1ereby the relay mechanism is actuated, actuationof said relay-mechanism causing closure of a second. path through therelay mechanism in parallel with the first path, said second pathii'icluding the tele I phonic apparatus, said iirst path being ofcurrent to the line and substations, telephonic apparatus at eachsubstation, relay mechanism controlling the connection of telephonicapparatus with the line, switchmg mechanism at each substation,actuation of the switching mechanism at one substation causing closureof one path through the relay mechanism whereby the relay mechanism isactuated, actuation of said relay mechanism causing closure of a secondpath through the relay mechanism in pan allel with the first path, saidsecond path including the telephonic apparatus, said first path being ofhigh resistance and the second path of low resistance whereby thegreater part of current. iiow through the substation will pass throughthe telephonic apparatus, the energy from said source upon closure ofthe low resistance path at the one substation being insufficient tocause actuation .of'tlie relay mechanism atany other substation throughthe highresistance path thereof whereby other substations are lockedfrom service, and auxiliary switching means at each substation,actuation of these auxiliary switching means at the one substationcausing opcning of the low resistance path to allow suilicient energy toHow through the high resistance path at any other substation uponactuation of the switching mechanism therea't whereby the relaymechanism at said other substation may be actuated to render 1 thetelephonic mechanism thereat eiiective.

24:. In a telephone system, the combination with a telephone line, ofsubstations colinected therewith, a source for supplying current to theline and substations, receiving and transmitting telephonic "apparatusat each substation, relay mechanism at each substation normally causingshort-circuiting of the receiving mechanism and disconnection from theline of the transmittingmechanism, main switching mechanism at eachsubstation, actuation of themain switching mechanism at one substationcausin closure of a high resistance path through t e relay mechanism tocause actuation of the relay mechanism to remove the short-circuit aboutthe receiving mechanism and to connect the transmitting mechanism Withthe circuit,

actuation of the relay mechanism causing closure of a low resistanceparallel path through the relay mechanism, the energy from said sourcebeing insufficient upon connection ofthe low resistance path at the onesubstation to Causeactuationof the relay mechanism at any othersubstation throu h the high resistance path thereof whereby t ereceiving mechanism at any other substation is maintained inshort-circuiting condition and the transmitting mechanism thereat keptdisconnected from the line.

25. In a telephone system, the combination with a telephone line, ofsubstations connected therewith, a source for supplying current to theline-and substations, receiving and transmitting telephonic apparatus ateach substation, relaymechamsm at each substation normally causingshort-circuiting of the receiving mechanism and. disconnedtion fromthelineof 'the'transmitting mechanism, main switching mechanism at eachsubstation,actuation' of the main switching mechanismat one subtationcausing closure of-a high resistance path through the relay mechanism tocause actuation of the relay mechanism to removelthe short-circuit aboutthe receiving mechanism and to connect the sistancepath thereof wherebythe receiving .of a high resistance path through the relay actuation olthe relay causing closure of a sec the relay and telephonic apparatus,said telephonic apparatus being thereby connected with the line. i

28 .In aparty line telephone system, a central source of electricenergy, line wires extending therefrom to a p stations, normallyinoperative tele honic apparatus at each substation, two windings, meanscontrolled by the relay for rendering the telephonic apparatusoperative, and a receiver and condenser in shunt of the said windings.

29. In a party line telephone system, a central source of electricenergy, line wires extending therefrom to a plurality of substations,normally inoperative telephonic apparatus at each substation, a relay ateach substation, and a switch controlled by said relay to close atelephonic circuit including a winding of said relay.

30. In a party line telephone system, a central source of electricenergy, line wires extending therefrom to a plurality of substations,telephonic apparatus at each ofsaid substations, an elcctromagnet ateach sub stat-ion, and switching mechanism controlled by eachelectromagnet and servingnormally to maintain the telephonic apparatusat the associated substation imperative, and serv ing when actuated bythe energization of said electromagnet to close a circuit including awinding of said electromagnet and telephonic apparatus.

31. In a party central source of electric energy, line wires extendingtherefrom to a plurality of substations, telephonic apparatus at each ofsai substations, an electromagnet at each sub-. station, and switchingmechanism controlled by each electromagnet and serving normally tomaintain associated substation inoperative, ing when actuated by the.energization of said electromagnet to close a circuit inc winding ofsaid electromagnetrand'a telephone transmitter.

32. In a party line telephone system, a central source of electricenergy, line wires extending therefrom to a plurality of substations,normally inoperative telephonic apparatus at each substation, a relay ateach substation, a switch controlled by said relay to close a telephoniccircuit including a winding of said relay, and a receiver and seriallyconnected condenser in shunt about a winding of the relay.

transmitting mechanism with the circuit, ac tuation of the relaymechanism causing closure of a low resistance parallel path through lthe relay mechanism, the energy from said i source being insufiicientupon connection of l the low resistance path at the one substation tocause actuation of the relay mechanism at any other substation. throughthe high re sistance path thereof whereby the receiving mechanism at anyother substation is maintained in short-circuiting condition and thetransmitting mechanism thereat kept disconnected from the line. andmeans at each substation for destroying the efi ect oi the lowresistance path to allow energization of the relay mechanism at othersubstations.

26. In a telephone system, the combina tion with a telephone line, ofsubstations connected therewith, a source for supplying current to theline and substations, receiving and transmitting telephonic apparatus ateach substation, relay mechanism at each substation normally causingshort-circuiting of the receiving mechanism and disconnection from theline of the transmitting mechanism, main switching mechanism at eachsubstation, actuation of the main switching mechanism at one substationcausing closure mechanism to cause actuation of the relay mechanism toremove the short-circuit about the receiving mechanism and to connectthe transmitting mechanism with the circuit, actuation oi the relaymechanism causing closure of a low resistance parallel path through therelay mechanism, the energy from said source being insufficient uponconnection oi thelow resistance path at the one substation to causeactuation of the relay mechanism at any other substation through thehigh remechanism at any other substation is main-v tained' inshort-circuiting condition and the transmitting mechanism thereat keptdisconnected from the line, said relay mechanism being of highimpedance, and a nonimpedance by-path at each substation for the passingtherethrough of Voice currents.

27. In a telephone system, the combination with a telephone line, of asubstation connected therewith, a source of current for connection withthe substation, main switching mechanism, and telephonic apparatus atthe substation, said telephonic apparatus being normally disconnectedfrom the line independently of the main switching mechanism, a relay forcontrolling the connection of the telephonic apparatus with the 1central source of electric energy, line wires line, said relay havingtwo windings, actuaextending therefromto a plurality of subtion of themain switching mechanism causstations, telephonic apparatus at each ofsaid ing the closure of a circuit through a winding 1 substations, anelectromagnet at stationfswitching mechanism controlled by each electro:magnet and serving normally to maintain the telephonic apparatus at theasrt the relay whereby said relay is actuated,

end circuit'through the substation, said se c sociated substationinoperatlve and serving and circuit including the other winding oflurality of sub line telephone system, a

ludlng a.

each suba relay aving the telephonic apparatus at the I and serv- 33. Ina party line telephone system, a

when actuated'by the encrgization of said electromagnet to close acircuit including a winding of said electromagnet and telephonicapparatus, and a recei'xer and serially connccted condenser in shuntabout a Winding of the relay. I

34. In a party line telephone system, a central source of electricenergy, line wires extending therefrom to a'plurality of substations,telephonic apparatus at each of said substations, an electromagnet ateach substation, switching mechanism controlled by each electromagnetand serving normally'to maintain the telephonic apparatus at theassociated substation inoperative, and servin when actuated by theenergization of saiv electromagnet to .close a circuit including awinding of said electromagnet and a telephone transmitter, and areceiver and serially connected condenser in shunt about a winding ofthe relay. Y

35. In combination, a telephone line leading from a plurality ofsubstations to a cen' tral ofiice, sources of talking and signalingcurrent at the central oflice, an electromagnet at eachof thesubstations, a signal bell at each substation, a condenser normally incircuit with each bell, switching means asso ciated with eachelectromagnet and adapted upon actuation of the associated-electromagnet to close a tele honic circuit including the condenser att e associated substa tion, and a receiver connected with each condenserin shunt of the winding of the associated electromagnet. I

36.. In combination, a telephone line lead-' ing from a plurality ofsubstations to a central otfice, sources of talking and signalingcurrent at the central ofiice, a relay at each substation-normallyinoperative, tele honic' apparatus at each substation, a signal ell ateach substation, a condenser normally in circuit with each 'bell, meansfor connectin apparatus causing closure of acircuit includ saidtelephonic apparatus in circuit with sai condenser, and means controlledby said relay to render'the telephonic apparatus operative.

37. In combination, a telephone line lead ing from a plurality ofsubstations to a central ofiice, sources of talking and signalingcurrent at the central oflice, a relay ateach substation normallyinoperative, telephonic apparatrs at each substation, switch a pa-'ratus at each substation, a signal bel at each substation, a condensernormally in cir cuit with each bell, actuation of the switch ing thecondenser and telephonic apparatus,

and means controlled by each relay to render operative saidtelephonic aparatus.

38. In combination, a te ephone line leading from a plurality ofsubstations to-a central oflice, sources of talking and signalingcurrent at the central office, a relay at each substation, telephonicapparatus at each substation comprising a receiver and transmitter,switch apparatus at each substation, a signal bell at each substation, acondenser normally in circuit with each signal bell, ac-- tuation of theswitch apparatus causing connection of said receiver in circuit with thecondenser and with the telephone line, and

laneans controlled by the relay for closing a circuit through thetransmitter and through one winding of said relay.

, '75 39. In combination, a telephone linedeading from a plurality ofsubstations to a cention of therclay with the line, and means adaptedupon energization of the relay to connect the .transmitter with the huethrough a circuit including a winding of the relay, said condenserserving to provide a IIOHflDClUCUVB path about the relay windlng.

40. In combination, a telephone line leadtral ofl'ice, sources oftalking and signaling current at the central ofiice, an electromagnet ateach substation normally inoperative,

telephonic apparatus at each substation comprising a transmitter and areceiver, switch mechanism at each substation, asignal bell at eachsubstation, a condenscr'normally in circuit with each bell, actuation ofthe switch mechanism closing a circuit through the relay, and a switchat each substation. controlled by the electromagnet when energized torender the telephonic apparatus operative, said switch when actu atedclosing also a circuit including a winding of the e ectromagnet and thetransmitter, actuation of the switch'mechanism closing ing from aplurality of substations to a con.-

also a circuit including the receiver and the condenser, v

41. In combination, a telephone line leading from a plurality ofsubstations to a central ofiice, a central source of electric energyconnected with the line at the central office, a

source of ringing current at the centraLofltice,

normally inoperative telephonic appa atus at each substation, comprisinga transmitter and a receiver, a relay at'each substation,

each relay being adapted upon actuation to render operative theassociated telephonic apparatus, a path at-ea'ch substation for ringingcurrents, a signal bell in each of said paths, a path at each substationin shunt around the relay winding for voice currents,

and a condenser common to both paths, the

' each substation, each relay adapted upon actuation to render operativethe assc iated telephonic apparatus, a path at each substa tion forringing currents, a signal bell in each of said paths, a path ateachsubstation in shunt around the relay windings for voice currents, acondenser common to.both paths,

the condenser and receiver being connected in shunt about said relaywindings, a manual switch at each substation for closing the circuitthrough one of the associated relay windings, and a switch controlled byeach relay to close the circuit through the other relay winding at eachsubstation. 43. In combination, a telephone line extending fromaplurality of substations to a central ofiice, sources of talking andsignaling I current at the central ofiice, normally inoperativetelephonic apparatus comprising aireceiver and transmitter at eachsubstation, a relay having two windings at each substation, means ateach substation adapted upon actuation'ot' the associated relay torender operative the associated. telephonic apparatus and to close acircuit including a winding of said relay and the transmitter, a path ateach substation in shunt around the relay windings for the passage ofvoice currents, and a condenser.common to both paths.

44. In combination, .a telephone line extending from a plurality ofsubstations to a central oilice, sources of talking and signalingcurrent at the central office, normally inoperative telepl'ionicapparatus comprising a receiver and transmitter at each substation, arelay at each substation, means at each substation adapted uponactuation of the associated relay to render operative the asso ciatedtelephonic apparatus and to close a circuit including a winding of saidrelay and. the transmitter, a path ateach substation for ringingcurrents, a path at each substation in shunt around a relay winding forthe passage of voice currents, and a condenser common to both paths.

45. In combination, a telephone line extending from a plurality ofsubstations to a central oflice, sources of talking and signalingcurrent at the central oiiice, normally ihoperative telephonic apparatuscomprising a receiver and transmitter at each substation, a relay havingtwo windings at each substation, means at each substation adapted uponactuation of the associated relay to-render operative the associatedtelephonic apparatus and to close a circuit including a winding of saidrelay and the transmitter, a path at each substation for ringingcurrents, a path. at each substation in shunt around. the relay windingsfor the passage of voice currents, a condenser common to both paths, amanual switch at each substation for closing circuit through one windingof the associated relay, and a switch controlled by each relay andadapted upon the strong energization of the relay to close circuitthrough the other relay Winding.

46. In combination, a telephone line'leading from a plurality ofsubstations to a central oflice, sources of talking and signalingcurrent at the central oiiice, a relay at each of said substationshaving two windings, a manual switch at each substation for closingthrough a winding of the associated relay a circuit in bridge of thetelephone line, and a switch controlled by said relay to close a circuitincluding the other winding of said relay and telephonic apparatus.

47. In combination, a telephone line'lead-' ing from a plurality ofsubstations to a central office,- sources 'of-talking and signalingcurrent at the central office connected with said line, a transmitter ateach substation,

an clectromagnet at each of said substa tions having two windings, amanual switch at each substation for closing through a winding of theassociated electromagnet a circuit in bridgeof the telephone line, and aswitch automatically controlled by each electromagnet and. adapted uponthe ener ization of the magnet to close a circuit irTeIuding the/ otherwinding of the electromagnet and the associated telephone transmitter.

48. In combination, a telephone line lead ing from a plurality ofsubstations to a cen-' tral oiiice, sources oftalking and signalingcurrent at the central ofiice connected with said line, a transmitter ateach substation, an eleetromagnet at each of said substations having twowindings, a manual switch at each substation for closing through awinding of the associated electromagnet a circuit in bridge of thetelephone line, a switch automatically controlled by each electromagnetand adapted upon energization of the mag net to close a circuitincluding the other winding of the electromagnet and the associatedtelephone transmittenand a receiver and :serially connected condenserconnected. in shunt of the otherwinding of said electromagnet.

49. In combination, a telephone line leading from a plurality ofsubstations to a central office, sources of talking and signalingcurrent at the central ofiice, a transmitter at each substation, anelectromagnet at each substation having a 'high resistance winding and a,low resistance winding, a manual swltch at each substation'for closingthrough ing from a plurality of substations to a cen-' tral oflice,sources of talking and signaling current at the central office, atransmitter at each substation, an e'lectromagnet at each substationhaving a high resistance winding and a low resistaneewinding, a manual Iswitch at each substation for closing through the high resistancewinding of the associated relay a circuit in bridge of the telephoneline, a switch controlled by each electromagnetand adapted upon theclosure of the high resistance circuitthrough one only of theelec'troniagnets'on a line to close a circuit through the low resistancewinding of the as sociated relay and the tele ihone transmitter, and areceiver and serially connected con-' denser connected in shunt of awinding of said electromagnet. i

51. In combination, a telephone line lead.- ing from a plurality ofsubstations to a central oflice, sources of talking and signalingcurrent at the central oll'ice connected with said line, a transmitterat each substation, an .electroinagnet at each ofsaid-substationshavingtwo windings, a manual switch at each substation for closingthrough a winding of the associated electromagnet a circuit in bridge ofthe telephone line, a switch automatically controlled by eachelectromagnet and adapted upon" the energizationof the magnet to close acircuit includin the other winding of the electroinagnet an theassosubstation having a high resistance winding and a low resistancewinding, a manual switch at each substation for, closing through thehigh resistance winding of the associated relay a circuit in brid e ofthe telephone line, a switch controlled by each electroinagnet andadapted upon the closure of the high resistance circuit through one onlyof the electromagiiet's on a line to close a circuit through theglowresistance winding of the associated, relay and the tele honetransmitter, and a receiver connecte in shunt of a winding ofsaidelectromagnet.

53. In aparty line telephone system, a central source'of electricenergy, line wires extending therefrom to a pluralityof substations,normally inoperative telephonic apparatus, at each substation, a relayat each sub-- station, a switch actuated by said relay ,to render thetelephonic apparatus operative, when said switch is in-its alternativeposition, a hookswitch,- magnetic means for maintaining said relaycontrolled switch in its alternative osition during'the time that saidswitch lioo is in its alternative position.

In witness whereof, I hereunto subscribe my name this eighteenth day ofDecember A .D.,190 5. a

I Armoar. POOLE. Witnesses: v I

FRANK B. HALL, I JNo. F. FRASHER.

